Copolycarbonate and composition containing the same

ABSTRACT

Disclosed is a copolycarbonate including an aromatic polycarbonate-based first repeating unit; and one or more aromatic polycarbonate-based second repeating units having siloxane bonds represented by Chemical Formula 2 and Chemical Formula 3: 
                         
The copolycarbonate provides improved impact strength at low-temperature and improved YI (yellow index) simultaneously.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a National Stage Application of International Application No. PCT/KR2015/012294, filed Nov. 16, 2015, and claims the benefit of Korean Patent Application No. 10-2015-0159660, filed Nov. 13, 2015, Korean Patent Application No. 10-2015-0104643, filed Jul. 23, 2015, and Korean Patent Application No. 10-2014-0173005, filed Dec. 4, 2014, the contents of which are incorporated herein by reference in their entirety for all purposes as if fully set forth below.

TECHNICAL FIELD

The present invention relates to a copolycarbonate and a composition comprising the same, and more specifically to a copolycarbonate being economically produced, and having improved impact strength at low-temperature and improved YI (yellow index) which are conflicting properties with each other, simultaneously, and to a composition comprising the same.

BACKGROUND OF ART

Polycarbonate resins are prepared by condensation-polymerization of an aromatic diol such as bisphenol A with a carbonate precursor such as a phosgene and have excellent impact strength, dimensional stability, heat resistance and transparency. Thus, the polycarbonate resins have application in a wide range of uses, such as exterior materials of electrical and electronic products, automobile parts, building materials, and optical components.

Recently, in order to apply these polycarbonate resins to more various fields, many studies have been made to obtain desired physical properties by copolymerizing two or more aromatic diol compounds having different structures from each other and introducing units having different structures in a main chain of the polycarbonate.

Especially, studies for introducing a polysiloxane structure in a main chain of the polycarbonate have been undergone, but most of these technologies have disadvantages in that production costs are high, and when chemical resistance or impact strength, particularly impact strength at low-temperature is increased, YI (yellow index) or the like is lowered.

Given the above circumstances, the present inventors have conducted intensive studies to overcome the above-mentioned disadvantages encountered with the prior arts and develop a copolycarbonate having improved impact strength at low-temperature and improved YI (yellow index), simultaneously, and found that a copolycarbonate in which a specific siloxane compound is introduced in a main chain of the polycarbonate as described below satisfies the above-described properties. The present invention has been completed on the basis of such a finding.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

It is an object of the present invention to provide a copolycarbonate having improved impact strength at low-temperature and improved YI (yellow index), simultaneously.

It is a further object of the present invention a composition comprising the above-mentioned copolycarbonate.

Technical Solution

In order to achieve these objects, the present invention provides a copolycarbonate described below:

(1) A copolycarbonate comprising: an aromatic polycarbonate-based first repeating unit; and one or more aromatic polycarbonate-based second repeating units having siloxane bonds, wherein the copolycarbonate has a YI (yellow index) of 2 to 6.5 as measured in accordance with ASTM D1925 and an impact strength at low-temperature of 600 to 1000 J/m as measured at −30° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).

Preferably, the YI (yellow index) is not less than 2, and is not more than 6.0, not more than 5.5, not more than 5.0, not more than 4.5, not more than 4.0, not more than 3.5, not more than 3.0, or not more than 2.5.

Also, preferably, the impact strength at low-temperature is not less than 600 J/m, not less than 650 J/m, not less than 700 J/m, not less than 710 J/m, not less than 720 J/m, not less than 730 J/m, not less than 740 J/m, or not less than 750 J/m. In addition, preferably, the impact strength at low-temperature is excellent when the value is high, and thus it is not limited to any upper limit value. As one example, however, it may be not more than 990 J/m, not more than 980 J/m, not more than 970 J/m, not more than 960 J/m, not more than 950 J/m, not more than 940 J/m, not more than 930 J/m, not more than 920 J/m, or not more than 910 J/m.

(2) Preferably, the copolycarbonate of the above item (1) wherein the copolycarbonate has an impact strength at room temperature of 840 to 1000 J/m as measured at 23° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).

More preferably, the impact strength at room temperature is not less than 850 J/m, not less than 860 J/m, not less than 870 J/m, not less than 880 J/m, not less than 890 J/m, not less than 900 J/m, not less than 910 J/m, not less than 920 J/m, not less than 930 J/m, not less than 940 J/m, not less than 950 J/m, or not less than 960 J/m. In addition, the impact strength at room temperature is excellent when the value is high, and thus it is not limited to any upper limit value. As one example, however, it may be not more than 990 J/m, not more than 980 J/m, or not more than 970 J/m.

(3) Also, preferably, the copolycarbonate of the above item (1) or (2) wherein the copolycarbonate has a weight average molecular weight of 1,000 to 100,000 g/mol, more preferably 15,000 to 35,000 g/mol. Within this range of the weight average molecular weight, the copolycarbonate has an effect of providing excellent ductility and YI (yellow index).

More preferably, the above weight average molecular weight is not less than 20,000 g/mol, not less than 21,000 g/mol, not less than 22,000 g/mol, not less than 23,000 g/mol, not less than 24,000 g/mol, not less than 25,000 g/mol, not less than 26,000 g/mol, not less than 27,000 g/mol, or not less than 28,000 g/mol. Also, the above weight average molecular weight is not more than 34,000 g/mol, not more than 33,000 g/mol, or not more than 32,000 g/mol.

(4) Further, preferably, the copolycarbonate of any one of the above items (1) to (3) comprising two kinds of aromatic polycarbonate-based second repeating units having siloxane bonds.

(5) Further, preferably, the copolycarbonate of any one of the above items (1) to (4) wherein the mole ratio of the aromatic polycarbonate-based first repeating unit and one or more aromatic polycarbonate-based second repeating units having siloxane bonds is 1:0.001-0.006, and/or the weight ratio thereof is 1:0.01-0.03.

(6) Further, preferably, the copolycarbonate of any one of the above items (1) to (5) wherein, in particular, the aromatic polycarbonate-based first repeating unit is formed by reacting an aromatic diol compound and a carbonate precursor, preferably the copolycarbonate represented by the following Chemical Formula 1:

in the Chemical Formula 1,

R₁, R₂, R₃ and R₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen,

Z is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂, or CO.

Preferably, R₁, R₂, R₃ and R₄ are each independently hydrogen, methyl, chloro, or bromo.

More preferably, Z is a linear or branched C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, and more preferably methylene, ethane-1,1-diyl, propane-2,2-diyl, butane-2,2-diyl, 1-phenylethane-1,1-diyl or diphenylmethylene. More preferably, Z is cyclohexane-1,1-diyl, O, S, SO, SO₂, or CO.

Preferably, the repeating unit represented by Chemical Formula 1 may be derived from one or more aromatic diol compounds selected from the group consisting of bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, bisphenol A, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, and α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.

As used herein, ‘derived from aromatic diol compounds’ means that a hydroxy group of the aromatic diol compound and a carbonate precursor are reacted to form the repeating unit represented by Chemical Formula 1.

For example, when bisphenol A which is an aromatic diol compound, and triphosgene which is a carbonate precursor, are polymerized, the repeating unit represented by Chemical Formula 1 is represented by the following Chemical Formula 1-1:

The carbonate precursor used herein may include one or more selected from the group consisting of dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl)carbonate, di-m-cresyl carbonate, dinaphthyl carbonate, bis(diphenyl)carbonate, phosgene, triphosgene, diphosgene, bromo phosgene and bishalo formate. Preferably, triphosgene or phosgene may be used.

(7) Further, preferably, the copolycarbonate of any one of the above items (1) to (6) wherein the one or more aromatic polycarbonate-based second repeating units having siloxane bonds are formed by reacting one or more siloxane compounds and a carbonate precursor, and it comprises preferably a repeating unit represented by the following Chemical Formula 2 and a repeating unit represented by the following Chemical Formula 3:

in the Chemical Formula 2,

each of X₁ is independently C₁₋₁₀ alkylene,

each of R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

n is an integer of 10 to 200,

in the Chemical Formula 3,

each of X₂ is independently C₁₋₁₀ alkylene,

each of Y₁ is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, C₁₋₆ alkoxy or C₆₋₂₀ aryl,

each of R₆ is independently hydrogen; or C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

m is an integer of 10 to 200.

In Chemical Formula 2, each of X₁ is independently preferably C₂₋₁₀ alkylene, more preferably C₂₋₄ alkylene and most preferably propane-1,3-diyl.

Also, preferably, each of R₅ is independently hydrogen, methyl, ethyl, propyl, 3-phenylpropyl, 2-phenylpropyl, 3-(oxiranylmethoxy)propyl, fluoro, chloro, bromo, iodo, methoxy, ethoxy, propoxy, allyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, or naphthyl. In addition, each of R₅ is independently preferably C₁₋₁₀ alkyl, more preferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl and most preferably methyl.

Further, preferably, n is an integer of not less than 10, not less than 15, not less than 20, not less than 25, not less than 30, not less than 31, or not less than 32; and not more than 50, not more than 45, not more than 40, not more than 39, not more than 38, or not more than 37.

In Chemical Formula 3, each of X₂ is independently preferably C₂₋₁₀ alkylene, more preferably C₂₋₆ alkylene and most preferably isobutylene.

Further, preferably, Y₁ is hydrogen.

Further, preferably, each of R₆ is independently hydrogen, methyl, ethyl, propyl, 3-phenylpropyl, 2-phenylpropyl, 3-(oxiranylmethoxy)propyl, fluoro, chloro, bromo, iodo, methoxy, ethoxy, propoxy, allyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, or naphthyl. Further, preferably, each of R₆ is independently C₁₋₁₀ alkyl, more preferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl, and most preferably methyl.

Preferably, m is not less than 40, not less than 45, not less than 50, not less than 55, not less than 56, not less than 57, or not less than 58; and not more than 80, not more than 75, not more than 70, not more than 65, not more than 64, not more than 63, or not more than 62.

The repeating unit represented by Chemical Formula 2 and the repeating unit represented by Chemical Formula 3 are, respectively, derived from a siloxane compound represented by the following Chemical Formula 2-1 and a siloxane compound represented by the following Chemical Formula 3-1:

In the Chemical Formula 2-1, X₁, R₅ and n are the same as previously defined.

In the Chemical Formula 3-1, X₂, Y₁, R₆ and m are the same as previously defined.

As used herein, ‘derived from a siloxane compound’ means that a hydroxy group of the respective siloxane compound and a carbonate precursor are reacted to form the repeating unit represented by Chemical Formula 2 and the repeating unit represented by the Chemical Formula 3. Further, the carbonate precursors that can be used for the formation of the repeating units represented by Chemical Formulae 2 and 3 are the same as those described for the carbonate precursor that can be used for the formation of the repeating unit represented by Chemical Formula 1 described above.

The methods for preparing the siloxane compound represented by Chemical Formula 2-1 and the siloxane compound represented by Chemical Formula 3-1 are represented by the following Reaction Schemes 1 and 2, respectively:

in the above Reaction Scheme 1,

X₁′ is C₂₋₁₀ alkenyl, and

X₁, R₅ and n are the same as previously defined.

in the above Reaction Scheme 2,

X₂′ is C₂₋₁₀ alkenyl, and

X₂, Y₁, R₆ and m are the same as previously defined.

In Reaction Scheme 1 and Reaction Scheme 2, the reaction is preferably conducted in the presence of a metal catalyst. As the metal catalyst, a Pt catalyst is preferably used. The Pt catalyst used herein may include one or more selected from the group consisting of Ashby catalyst, Karstedt catalyst, Lamoreaux catalyst, Speier catalyst, PtCl₂(COD), PtCl₂(benzonitrile)₂ and H₂PtBr₆. The metal catalyst may be used in an amount of not less than 0.001 parts by weight, not less than 0.005 parts by weight, or not less than 0.01 parts by weight; and not more than 1 part by weight, not more than 0.1 part by weight, or not more than 0.05 part by weight, based on 100 parts by weight of the compounds represented by the Chemical Formulae 7 or 9.

Further, the above reaction temperature is preferably 80 to 100° C. Further, the above reaction time is preferably 1 to 5 hours.

In addition, the compounds represented by Chemical Formulae 7 or 9 can be prepared by reacting an organodisiloxane and an organocyclosiloxane in the presence of an acid catalyst, and n and m may be adjusted by adjusting the amount of the reactants. The reaction temperature is preferably 50 to 70° C. Also, the reaction time is preferably 1 to 6 hours.

The above organodisiloxane may include one or more selected from the group consisting of tetramethyldisiloxane, tetraphenyldisiloxane, hexamethyldisiloxane and hexaphenyldisiloxane. In addition, the above organocyclosiloxane may include, for example, organocyclotetrasiloxane. As one example thereof, octamethylcyclotetrasiloxane and octaphenylcyclotetrasiloxane and the like can be included.

The above organodisiloxane can be used in an amount of not less than 0.1 parts by weight or not less than 2 parts by weight; and not more than 10 parts by weight or not more than 8 parts by weight, based on 100 parts by weight of the organocyclosiloxane.

The above acid catalyst that may be used herein includes one or more selected from the group consisting of H₂SO₄, HClO₄, AlCl₃, SbCl₅, SnCl₄ and acid clay (fuller's earth). Further, the acid catalyst may be used in an amount of not less than 0.1 parts by weight, not less than 0.5 parts by weight or not less than 1 part by weight; and not more than 10 parts by weight, not more than 5 parts by weight or not more than 3 parts by weight, based on 100 parts by weight of the organocyclosiloxane.

In particular, by adjusting the content of the repeating unit represented by Chemical Formula 2 and the repeating unit represented by Chemical Formula 3, the impact strength at low-temperature and YI (yellow index) of the copolycarbonate can be improved simultaneously. Preferably, the weight ratio between the repeating units may be from 1:99 to 99:1. Preferably, the weight ratio is from 3:97 to 97:3, from 5:95 to 95:5, from 10:90 to 90:10, or from 15:85 to 85:15, and more preferably from 20:80 to 80:20. The weight ratios of the above repeating units correspond to the weight ratios of siloxane compounds, for example the siloxane compound represented by Chemical Formula 2-1 and the siloxane compound represented by Chemical Formula 3-1.

Preferably, the repeating unit represented by Chemical Formula 2 is represented by the following Chemical Formula 2-2:

In the Chemical Formula 2-2, R₅ and n are the same as previously defined. Preferably, R₅ is methyl.

Also, preferably, the repeating unit represented by Chemical Formula 3 is represented by the following Chemical Formula 3-2:

In the Chemical Formula 3-2, R₆ and m are the same as previously defined. Preferably, R₆ is methyl.

(8) Further, the present invention provides a copolycarbonate including all of the repeating unit represented by Chemical Formula 1-1, the repeating unit represented by Chemical Formula 2-2, and the repeating unit represented by Chemical Formula 3-2. Further, it provides the copolycarbonate of any one of the above items (1) to (7) wherein the copolycarbonate comprises all of the repeating unit represented by Chemical Formula 1-1, the repeating unit represented by Chemical Formula 2-2, and the repeating unit represented by Chemical Formula 3-2.

(9) Further, the present invention provides a method for preparing a copolycarbonate comprising a step of polymerizing the aromatic diol compound, the carbonate precursor and one or more siloxane compounds.

The aromatic diol compound, the carbonate precursor and the one or more siloxane compounds are the same as previously described.

During the polymerization, the one or more siloxane compounds can be used in an amount of not less than 0.1% by weight, not less than 0.5% by weight, not less than 1% by weight or not less than 1.5% by weight; and not more than 20% by weight, not more than 10% by weight, not more than 7% by weight, not more than 5% by weight, not more than 4% by weight, not more than 3% by weight or not more than 2% by weight, based on 100% by weight in total of the aromatic diol compound, the carbonate precursor and the one or more siloxane compounds. Also, the above aromatic diol compound can be used in an amount of not less than 40% by weight, not less than 50% by weight, or not less than 55% by weight; and not more than 80% by weight, not more than 70% by weight, or not more than 65% by weight, based on 100% by weight in total of the aromatic diol compound, the carbonate precursor and the one or more siloxane compounds. The above carbonate precursor can be used in an amount of not less than 10% by weight, not less than 20% by weight, or not less than 30% by weight; and not more than 60% by weight, not more than 50% by weight, or not more than 40 by weight, based on 100% by weight in total of the aromatic diol compound, the carbonate precursor and the one or more siloxane compounds.

Further, as the polymerization method, an interfacial polymerization method can be used as one example. In this case, there is an effect in that the polymerization reaction is possible at a low temperature under an atmospheric pressure, and the molecular weight is easily controlled. The above interfacial polymerization is preferably conducted in the presence of an acid binder and an organic solvent. Furthermore, the above interfacial polymerization may comprise, for example, the steps of conducting pre-polymerization, then adding a coupling agent and again conducting polymerization. In this case, the copolycarbonate having a high molecular weight can be obtained.

The materials used in the interfacial polymerization are not particularly limited as long as they can be used in the polymerization of polycarbonates. The used amount thereof may be controlled as required.

The acid binding agent may include, for example, alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, or amine compounds such as pyridine.

The organic solvent is not particularly limited as long as it is a solvent that can be usually used in the polymerization of polycarbonate. As one example, halogenated hydrocarbon such as methylene chloride or chlorobenzene can be used.

Further, during the interfacial polymerization, a reaction accelerator, for example, a tertiary amine compound such as triethylamine, tetra-n-butyl ammonium bromide and tetra-n-butylphosphonium bromide or a quaternary ammonium compound or a quaternary phosphonium compound may be further used for accelerating the reaction.

In the interfacial polymerization, the reaction temperature is preferably from 0 to 40° C. and the reaction time is preferably from 10 minutes to 5 hours. Further, during the interfacial polymerization reaction, pH is preferably maintained at not less than 9, or not less than 11.

In addition, the interfacial polymerization may be conducted by further including a molecular weight modifier. The molecular weight modifier may be added before the initiation of polymerization, during the initiation of polymerization, or after the initiation of polymerization.

As the above molecular weight modifier, mono-alkylphenol may be used. As one example, the mono-alkylphenol is one or more selected from the group consisting of p-tert-butylphenol, p-cumyl phenol, decyl phenol, dodecyl phenol, tetradecyl phenol, hexadecyl phenol, octadecyl phenol, eicosyl phenol, docosyl phenol and triacontyl phenol, and preferably p-tert-butylphenol. In this case, the effect of adjusting the molecular weight control is great.

The above molecular weight modifier is contained, for example, in an amount of not less than 0.01 parts by weight, not less than 0.1 parts by weight or not less than 1 part by weight, and in an amount of not more than 10 parts by weight, not more than 6 parts by weight, or not more than 5 parts by weight, based on 100 parts by weight of the aromatic diol compound. Within this range, the required molecular weight can be obtained.

(10) In addition, the present invention provides a polycarbonate composition comprising the above-mentioned copolycarbonate and polycarbonate.

The copolycarbonate may be used alone, but it can be used together with the polycarbonate as needed to control the physical properties of the copolycarbonate.

The above polycarbonate does not introduce a polysiloxane structure in a main chain of the polycarbonate. In this regard, it is distinguished from the copolycarbonate according to the present invention.

Preferably, the above polycarbonate comprises a repeating unit represented by the following Chemical Formula 4:

in the Chemical Formula 4,

R′₁, R′₂, R′₃ and R′₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen,

Z′ is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂ or CO.

Further, preferably, the above polycarbonate has a weight average molecular weight of 15,000 to 35,000 g/mol. More preferably, the above weight average molecular weight (g/mol) is not less than 20,000, not less than 21,000, not less than 22,000, not less than 23,000, not less than 24,000, not less than 25,000, not less than 26,000, not less than 27,000, or not less than 28,000. Further, the above weight average molecular weight (g/mol) is not more than 34,000, not more than 33,000, or not more than 32,000.

The repeating unit represented by Chemical Formula 4 is formed by reacting the aromatic diol compound and the carbonate precursor. The aromatic diol compound and the carbonate precursor that can be used herein are the same as previously described for the repeating unit represented by Chemical Formula 1.

Preferably, R′₁, R′₂, R′₃, R′₄ and Z′ in Chemical Formula 4 are the same as previously described for R₁, R₂, R₃, R₄ and Z in Chemical Formula 1, respectively.

Further, preferably, the repeating unit represented by Chemical Formula 4 is represented by the following Chemical Formula 4-1:

In the polycarbonate composition, the weight ratio of the copolycarbonate and the polycarbonate is preferably from 99:1 to 1:99, more preferably from 90:10 to 50:50, and most preferably from 80:20 to 60:40.

(11) In addition, the present invention provides an article comprising the above-mentioned copolycarbonate or the copolycarbonate composition.

Preferably, the above article is an injection molded article. In addition, the article may further comprise, for example, one or more selected from the group consisting of antioxidants, heat stabilizers, light stabilizers, plasticizers, antistatic agents, nucleating agents, flame retardants, lubricants, impact reinforcing agents, fluorescent brightening agents, ultraviolet absorbers, pigments and dyes.

The method for preparing the article may comprise the steps of mixing the copolycarbonate according to the present invention and additives such as antioxidants using a mixer, extrusion-molding the mixture with an extruder to produce a pellet, drying the pellet and then injecting the dried pellet with an injection molding machine.

Advantageous Effects

As set forth above, according to the present invention, the copolycarbonate in which a specific siloxane compound is introduced in a main chain of the polycarbonate has characteristics of providing improved impact strength at low-temperature and improved yellow index (YI), simultaneously.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Below, preferred embodiments will be provided in order to assist in the understanding of the present disclosure. However, these examples are provided only for illustration of the present invention, and should not be construed as limiting the present invention by the examples.

Preparation Example 1: AP-PDMS (n=34)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 2.40 g (17.8 mmol) of tetramethyldisiloxane were mixed. The mixture was then placed in 3 L flask together with 1 part by weight of an acid clay (DC-A3) compared to 100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60° C. for 4 hours. After completion of the reaction, the reaction product was diluted with ethyl acetate and quickly filtered using a celite. The repeating unit (n) of the unmodified polyorganosiloxane thus prepared was 34 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 4.81 g (35.9 mmol) of 2-allylphenol and 0.01 g (50 ppm) of Karstedt's platinum catalyst were added and reacted at 90° C. for 3 hours. After completion of the reaction, the unreacted siloxane was removed by conducting evaporation under the conditions of 120° C. and 1 torr. The terminal-modified polyorganosiloxane thus prepared was designated as AP-PDMS (n=34). AP-PDMS was a pale yellow oil and the repeating unit (n) was 34 when confirmed through ¹H NMR using a Varian 500 MHz, and further purification was not required.

Preparation Example 2: MBHB-PDMS (m=58)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.5 g (11 mmol) of tetramethyldisiloxane were mixed. The mixture was then introduced in 3 L flask together with 1 part by weight of an acid clay (DC-A3) compared to 100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60° C. for 4 hours. After completion of the reaction, the reaction product was diluted with ethyl acetate and quickly filtered using a celite. The repeating unit (m) of the terminal-unmodified polyorganosiloxane thus prepared was 58 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7 mmol) of 3-methylbut-3-enyl 4-hydroxybenzoate and 0.01 g (50 ppm) of Karstedt's platinum catalyst were added and reacted at 90° C. for 3 hours. After completion of the reaction, the unreacted siloxane was removed by conducting evaporation under the conditions of 120° C. and 1 torr. The terminal-modified polyorganosiloxane thus prepared was designated as MBHB-PDMS (m=58).

MBHB-PDMS was a pale yellow oil and the repeating unit (m) was 58 when confirmed through ¹H NMR using a Varian 500 MHz, and further purification was not required.

Preparation Example 3: Eugenol-PDMS

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.7 g (13 mmol) of tetramethyldisiloxane were mixed. The mixture was then placed in 3 L flask together with 1 part by weight of an acid clay (DC-A3) compared to 100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60° C. for 4 hours. After completion of the reaction, the reaction product was diluted with ethyl acetate and quickly filtered using a celite. The repeating unit (n) of the terminal-unmodified polyorganosiloxane thus prepared was 50 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7 mmol) of Eugenol and 0.01 g (50 ppm) of Karstedt's platinum catalyst were added and reacted at 90° C. for 3 hours. After completion of the reaction, the unreacted siloxane was removed by conducting evaporation under the conditions of 120° C. and 1 torr. The terminal-modified polyorganosiloxane thus prepared was designated as Eugenol-PDMS. Eugenol-PDMS was a pale yellow oil and the repeating unit (n) was 50 when confirmed through ¹H NMR using a Varian 500 MHz, and further purification was not required.

Example 1

1784 g of water, 385 g of NaOH and 232 g of BPA (bisphenol A) were added to a polymerization reactor and dissolved with mixing under a N₂ atmosphere. 4.3 g of PTBP (para-tert butylphenol) and a mixed solution (weight ratio of 90:10) of 5.91 g of AP-PDMS (n=34) prepared in Preparation Example 1 and 0.66 g of MBHB-PDMS (m=58) prepared in Preparation Example 2 were dissolved in MC (methylene chloride) and then added thereto. Subsequently, 128 g of TPG (triphosgene) was dissolved in MC and a dissolved TPG solution was added thereto and reacted for 1 hour while maintaining pH of the TPG solution at 11 or more. After 10 minutes, 46 g of TEA (triethylamine) was added thereto to conduct a coupling reaction. After a total reaction time of 1 hour and 20 minutes, pH was lowered to 4 to remove TEA, and then pH of a produced polymer was adjusted to neutral pH of 6 to 7 by washing three times with distilled water. The polymer thus obtained was re-precipitated in a mixed solution of methanol and hexane, and then dried at 120° C. to give a final copolycarbonate.

Example 2

The copolycarbonate was prepared in the same method as in Example 1, except that an additive (antioxidant, lubricant) was added.

Example 3

The copolycarbonate was prepared in the same method as in Example 1, except that the ratio of AP-PDMS and MBHB-PDMS was 95:5 instead of 90:10.

Example 4

The copolycarbonate was prepared in the same method as in Example 3, except that the used amount of of the molecular weight modifier (PTBT) was adjusted.

Comparative Example 1

1784 g of water, 385 g of NaOH and 232 g of BPA (bisphenol A) were added to a polymerization reactor, and dissolved with mixing under a N₂ atmosphere. 4.3 g of PTBP (para-tert butylphenol) and 6.57 g of Eugenol-PDMS prepared in Preparation Example 3 was dissolved in MC (methylene chloride) and then added thereto. Subsequently, 128 g of TPG (triphosgene) was dissolved in MC and a dissolved TPG solution was added thereto and reacted for 1 hour while maintaining pH of the TPG solution at 11 or more. After 10 minutes, 46 g of TEA (triethylamine) was added thereto to conduct a coupling reaction. After a total reaction time of 1 hour and 20 minutes, pH was lowered to 4 to remove TEA, and the pH of a produced polymer was adjusted to neutral pH of 6-7 by washing three times with distilled water. The polymer thus obtained was re-precipitated in a mixed solution of methanol and hexane, and then dried at 120° C. to give a final copolycarbonate.

Comparative Example 2

The copolycarbonate was prepared by the same method as in Comparative Example 1, except that AP-PDMS (n=34) prepared in Preparation Example 1 was used instead of Eugenol-PDMS prepared in Preparation Example 3.

Experimental Example: Confirmation of Characteristics of Copolycarbonate

The weight average molecular weight of the copolycarobate prepared in the Examples and Comparative Examples were measured by GPC using PC Standard with Agilent 1200 series.

In addition, with respect to 1 part by weight of the respective copolycarbonate prepared in the Examples and Comparative Examples, 0.050 parts by weight of tris(2,4-di-tert-butylphenyl)phosphite, 0.010 parts by weight of octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 0.030 parts by weight of pentaerythritol tetrastearate were added thereto, and the resulting mixture was pelletized using a φ30 mm twin-screw extruder provided with a vent, and was injection-molded at a cylinder temperature of 300° C. and a mold temperature of 80° C. using the N-20C injection molding machine of JSW Co., Ltd to prepare a desired specimen.

The characteristics of the above specimens were measured in the following manner and the results were shown in Table 1 below.

1) Impact strength at room temperature: measured at 23° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).

2) Impact strength at low-temperature: measured at −30° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).

3) YI (yellow index): Specimen (width/length/thickness=60 mm/40 mm/3 mm) was injection-molded at 300° C., and then YI (Yellow Index) was measured under the following conditions by using Color-Eye 7000A (X-rite Inc.) in accordance with ASTM D1925.

-   -   Measurement temperature: room temperature (23° C.)     -   Aperture size: Large area of view     -   Measurement method: transmittance was measured in a spiral range         (360 nm to 750 nm)

TABLE 1 Comparative Comparative Exampe 1 Example 2 Example 3 Example 4 Example 1 Example 2 Impact strength 963.2 932.8 889.0 845.0 802.1 650.7 at room temperature (J/m) Impact strength 902.2 864.7 731.5 678.0 678.5 533.1 at low-temperature (J/m) YI (Yellow Index) 6.27 5.55 3.11 2.43 6.74 3.71 Weight average 31,500 31,400 30,200 28,100 26,100 24,900 molecular weight (g/mol)

As shown in Table 1 above, it could be confirmed that the copolycarbonate according to the present invention (Examples 1 to 4) exhibited excellent impact strength at low-temperature and impact strength at room temperature as compared with Comparative Examples 1 and 2; Examples 1 and 2 had improved YI (Yellow Index) while maintaining an impact strength at low-temperature as compared with Comparative Example 1; and Examples 3 and 4 had improved YI (Yellow Index) while maintaining an impact strength at low-temperature as compared with Comparative Example 2.

Therefore, it could be confirmed that the copolycarbonate according to the present invention could have improved impact strength at low-temperature and improved YI (Yellow Index) simultaneously. 

The invention claimed is:
 1. A copolycarbonate comprising: an aromatic polycarbonate-based first repeating unit; and one or more aromatic polycarbonate-based second repeating units having siloxane bonds, wherein the copolycarbonate has a YI (yellow index) of 2 to 6.5 as measured in accordance with ASTM D1925, and an impact strength at low-temperature of 600 to 1000 J/m as measured at −30° C. in accordance with ASTM D256 (⅛ inch, Notched Izod), and wherein the second repeating unit comprises a repeating unit represented by Chemical Formula 2 and a repeating unit represented by Chemical Formula 3:

in Chemical Formula 2, each of X₁ is independently C₁₋₁₀ alkylene, each of R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and n is an integer of 10 to 200,

in Chemical Formula 3, each of X₂ is independently C₁₋₁₀ alkylene, each of Y₁ is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, C₁₋₆ alkoxy or C₆₋₂₀ aryl, each of R₆ is independently hydrogen; or C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and m is an integer of 10 to
 200. 2. The copolycarbonate of claim 1 wherein the copolycarbonate has an impact strength at room temperature of 840 to 1000 J/m as measured at 23° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).
 3. The copolycarbonate of claim 1 wherein the copolycarbonate has a weight average molecular weight of 1,000 to 100,000 g/mol.
 4. The copolycarbonate of claim 1 wherein the first repeating unit is represented by Chemical Formula 1:

in Chemical Formula 1, R₁, R₂, R₃ and R₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen, and Z is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂, or CO.
 5. The copolycarbonate of claim 4 wherein the repeating unit represented by Chemical Formula 1 is derived from one or more aromatic diol compounds selected from the group consisting of bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, bisphenol A, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, and α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.
 6. The copolycarbonate of claim 4 wherein the Chemical Formula 1 is represented by the following Chemical Formula 1-1:


7. The copolycarbonate of claim 1 wherein the weight ratio of the repeating unit represented by Chemical Formula 2 and the repeating unit represented by Chemical Formula 3 is 1:99 to 99:1.
 8. The copolycarbonate of claim 1 wherein the repeating unit represented by Chemical Formula 2 is represented by the following Chemical Formula 2-2:


9. The copolycarbonate of claim 1 wherein the repeating unit represented by Chemical Formula 3 is represented by the following Chemical Formula 3-2:


10. A polycarbonate composition comprising the copolycarbobnate of claim 1 and a polycarbonate.
 11. The polycarbonate composition of claim 10 wherein the polycarbonate does not introduce a polysiloxane structure in a main chain of the polycarbonate.
 12. The polycarbonate composition of claim 10 wherein the polycarbonate comprises a repeating unit represented by Chemical Formula 4:

in Chemical Formula 4, R′₁, R′₂, R′₃ and R′₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy or halogen, and Z′ is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted by C₁₋₁₀ alkyl, O, S, SO, SO₂ or CO. 